Liposomal doxorubicin (CaelyxR) in symptomatic androgen-independent prostate cancer (AIPC) -: Delayed response and flare phenomenon should be considered

Background: Compared with the native drug, liposomal PEG-coated doxorubicin (Caelyx(R)) enhances tumour activity and reduces toxicity. The formulation may therefore be beneficial in anthracycline-sensitive malignancies, where toxicity represents a major problem, as is the case in androgen-insensitive prostate cancer (AIPC). Methods: In a multi-centre design 28 patients with advanced AIPC received Caelyx 40 mg/m(2) as a 1-hour infusion every month. PSA-based biochemical and subjective response was recorded. Results: Three patients had biochemical responses, a subjective response was recorded in a fourth patient. No Grade 4 toxicity was encountered. Three patients developed a spontaneously recovering plantar-palmar erythema. In 3 of the 4 responding patients. the nadir PSA value was noted after 12 and 16 weeks, respectively. A possible flare phenomenon for PSA was evident in 4 patients. Conclusion: Caelyx(R) has limited activity in advanced AIPC. Due to its low toxicity profile the drug may be a worthwhile component of combination treatment of this chemotherapy-resistant condition. In general, clinicians should be aware of possible delay in PSA response as well as possible flare phenomenon during investigational systemic treatment of AIPC. Furthermore, standardization of blood sampling and PSA analyses are necessary in future therapeutic trials of AIPC.